Private Sub Worksheet_SelectionChange(ByVal Target As Range)
If Target.Count = 1 And Not Intersect([Q11:R31], Target) Is Nothing Then
If Target.Column = 17 Then
If Target = "" Then Target = "X": Target.Offset(0, 1) = "" Else Target = "": Target.Offset(0, 1) = "X"
End If
If Target.Column = 18 Then
If Target = "" Then Target = "X": Target.Offset(0, -1) = "" Else Target = "": Target.Offset(0, -1) = "X"
End If
End If
' ci-dessous le bout de code qui répond à la question posée
If Target.Count = 1 And Not Intersect([T11:Z31], Target) Is Nothing Then
If Cells(Target.Row, 17) = "" And Cells(Target.Row, 18) = "" Then MsgBox ("Veuillez mettre une croix en colonne JOUR : NUIT")
End If